The next, JG1111 was a demo model which went to Trident Studios off Wardour Street, London.
John Gustafson's fretted JG was next, JG1112 - he later returned for a fretless, JG1131.
The S and E serial number prefix Korean Squiers are from the late 1980s/early 1990s. M – The first number following the prefix is the year. Used in early 90's, featured the a high gloss maple neck with a slimmer 40mm body made from plywood.
Example: M1xxxxxx = 1991 No prefix – The first 2 numbers following the prefix is the year. The plant from which the COB serial number prefix models originate remains a mystery.
The only way to try to narrow the date range of your specific instrument is to remove the neck and check the butt end of the neck heel for a production date, which may be stamped or written there (if you`re uncomfortable doing this yourself, please refer to an experienced professional guitar tech in your area). Serial numbering didn`t change immediately because instruments continued to be made using existing, tooling, parts and serial number schemes.
While there have been periods of dramatic change—such as the transition periods between the Leo Fender years and the CBS years or the transition between the CBS years and the current ownership—most models are generally feature-specific and do not change from year to year.
Serial numbers are also helpful in determining an instrument`s production year.
If you happen to own a Custom Series Bass your job is very, very simple...
Just take the control cavity plate off the back off your bass and you should find a small piece of masking tape with all the info you need (and more) written on it! The masking tape is written by whoever happened to give the bass it's final check and once-over.
The chart below details Fender serial number schemes used from 1965 to 1976.